Devices and methods related to directional couplers

ABSTRACT

Devices and methods related to directional couplers. In some implementations, a coupler can include a driver arm and a coupler arm implemented relative to the driver arm to detect power of an RF signal. Portions of the driver and coupler arms can form an overlapping region, with at least one of the driver and coupler arms having a non-straight arm shape. The overlapping region can include a non-zero lateral offset between the driver and coupler arms. In some implementations, a coupler can include a driver arm having input and output sides, and a coupler arm having input and output sides and implemented relative to the driver arm to detect power of an RF signal. The coupler can further include a phase-shifting feature implemented with respect to at least one of the driver and coupler arms to reduce phase difference of power ripples associated with the coupler.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/011,372 filed Jun. 12, 2014 entitled CIRCUITS AND METHODS RELATED TODIRECTIONAL CHAIN COUPLERS, the disclosure of which is hereby expresslyincorporated by reference herein in its entirety.

BACKGROUND

1. Field

The present disclosure generally relates to directional couplers forradio-frequency (RF) applications.

2. Description of the Related Art

In some wireless devices, power couplers can be used to, for example,adjust power of transmitted signals for a plurality of bands. Such powercouplers can be daisy-chained together to share a coupled line, tothereby space on a circuit board.

SUMMARY

In some implementations, the present disclosure relates to a coupler fordetecting power of a radio-frequency (RF) signal. The coupler includes adriver arm configured to route the RF signal, and a coupler armimplemented relative to the driver arm to detect a portion of the powerof the RF signal. Portions of the driver arm and the coupler arm form anoverlapping region, and at least one of the driver and coupler arms havea non-straight arm shape. The overlapping region includes a non-zerolateral offset between the driver and coupler arms.

In some embodiments, the non-straight arm shape can include a straightsection and a first side loop extending parallel with the straightsection implemented as part of the driver arm. The non-straight armshape can further include a second side loop extending parallel with thestraight section to form a Phi shape.

In some embodiments, the driver arm can include a C-shape as thenon-straight arm shape. The coupler arm can include a C-shape as thenon-straight arm shape. The C-shapes of the driver and coupler arms canbe arranged in a back-to-back configuration such that portions ofstraight sections of the C-shapes form the overlapping region. Thelateral offset can include the straight sections of the C-shapes beingmoved away from each other.

In some embodiments, the driver arm can include a 7-shape as thenon-straight arm shape. The coupler arm can include a straight sectionthat forms the overlapping region with a straight section of the7-shape.

In some embodiments, the coupler can further include a phase-shiftingfeature implemented with respect to at least one of the driver andcoupler arms to reduce a difference in phases of power ripplesassociated with the driver and coupler arms.

According to a number of implementations, the present disclosure relatesto a radio-frequency (RF) module that includes a packaging substratehaving multiple layers, and a plurality of power amplifiers (PAs)implemented on the packaging substrate. The RF module further includes acoupler assembly implemented relative to the packaging substrate andincluding a first coupler configured to detect power of an RF signalamplified by a first PA. The first coupler includes a driver armconfigured to route the RF signal, and a coupler arm implementedrelative to the driver arm to detect a portion of the power of the RFsignal. Portions of the driver arm and the coupler arm form anoverlapping region, and at least one of the driver and coupler arms havea non-straight arm shape. The overlapping region includes a non-zerolateral offset between the driver and coupler arms.

In some embodiments, the packaging substrate can include a laminatesubstrate having four or more layers having a layer number i beginningwith 1 for the uppermost layer. The driver arm can be implemented overan i-th layer, and the coupler arm can be implemented below the i-thlayer. The value of i can be greater than or equal to 2, or greater thanor equal to 3.

In some embodiments, the coupler assembly can further include a signalpath trace for one side of the coupler arm, with the signal path tracebeing configured to improve directivity performance of the couplerassembly. The coupler assembly can further include a second couplerconfigured to detect power of an RF signal amplified by a second PA. Thesecond coupler can include a driver arm configured to route the RFsignal, and a coupler arm implemented relative to the driver arm todetect a portion of the power of the RF signal. Portions of the driverarm and the coupler arm of the second coupler can form an overlappingregion, with at least one of the driver and coupler arms having anon-straight arm shape. The overlapping region can include a non-zerolateral offset between the driver and coupler arms.

In some embodiments, the first coupler and the second coupler can beconnected in a chain configuration. The signal path trace for the firstcoupler can be an input for the chain configuration of the first andsecond couplers. The coupler assembly can further include a signal pathtrace for an output side of the coupler arm of the second coupler, andthe signal path trace can be configured to improve directivityperformance of the coupler assembly.

In some embodiments, the coupler assembly can further include aphase-shifting feature implemented with respect to at least one of thedriver and coupler arms of the first coupler to reduce a difference inphases of power ripples associated with the driver and coupler arms. Insome embodiments, the RF module can be a front-end module.

In accordance with some teachings, the present disclosure relates to aradio-frequency (RF) device that includes a transceiver configured toprocess RF signals, and an antenna in communication with thetransceiver. The antenna is configured to facilitate transmission of anamplified RF signal. The RF device further includes an RF moduleconnected to the transceiver. The RF module is configured to generateand route the amplified RF signal to the antenna. The RF module includesa coupler configured to detect power of the amplified RF signal. Thecoupler includes a driver arm configured to route the amplified RFsignal, and a coupler arm implemented relative to the driver arm todetect a portion of the power of the amplified RF signal. Portions ofthe driver arm and the coupler arm form an overlapping region, and atleast one of the driver and coupler arms has a non-straight arm shape.The overlapping region includes a non-zero lateral offset between thedriver and coupler arms. In some embodiments, the RF device can be awireless device.

In a number of implementations, the present disclosure relates to acoupler for detecting power of a radio-frequency (RF) signal. Thecoupler includes a driver arm having input and output sides, and isconfigured to route the RF signal. The coupler further includes acoupler arm having input and output sides, and implemented relative tothe driver arm to detect a portion of the power of the RF signal. Thecoupler further includes a phase-shifting feature implemented withrespect to at least one of the driver and coupler arms to reduce adifference in phases of power ripples associated with the driver andcoupler arms.

In some embodiments, the power ripple associated with the driver arm caninclude a power ripple on the output side of the driver arm. The powerripple associated with the coupler arm can include a power ripple on theoutput side of the coupler arm.

In some embodiments, the phase-shifting feature can include a curvedfeature associated with the corresponding arm. The curved feature can bepart of the corresponding arm. The curved feature can overlap with atleast a portion of the other arm. The curved feature can havesubstantially nil overlap with the other arm.

In some embodiments, the curved feature can be part of a connection toor from the corresponding arm. The curved feature can include a partialloop. The curved feature can include at least one loop.

In some embodiments, at least some portions of the driver arm and thecoupler arm can form an overlapping region, and at least one of thedriver and coupler arms can have a non-straight arm shape. Theoverlapping region can include a non-zero lateral offset between thedriver and coupler arms.

In a number of implementations, the present disclosure relates to aradio-frequency (RF) module that includes a packaging substrate havingmultiple layers, and a plurality of power amplifiers (PAs) implementedon the packaging substrate. The RF module further includes a couplerassembly implemented relative to the packaging substrate and including afirst coupler configured to detect power of an RF signal amplified by afirst PA. The first coupler includes a driver arm having input andoutput sides, and a coupler arm having input and output sides andimplemented relative to the driver arm to detect a portion of the powerof the RF signal. The first coupler further includes a phase-shiftingfeature implemented with respect to at least one of the driver andcoupler arms to reduce a difference in phases of power ripplesassociated with the driver and coupler arms.

In some embodiments, the packaging substrate can include a laminatesubstrate having four or more layers having a layer number i beginningwith 1 for the uppermost layer. The driver arm can be implemented overan i-th layer, and the coupler arm can be implemented below the i-thlayer. The value of i can be greater than or equal to 2, or greater thanor equal to 3.

In some embodiments, the coupler assembly can further include a signalpath trace for one side of the coupler arm, and the signal path tracecan be configured to improve directivity performance of the couplerassembly. The coupler assembly can further include a second couplerconfigured to detect power of an RF signal amplified by a second PA. Thesecond coupler can include a driver arm configured to route the RFsignal, and a coupler arm implemented relative to the driver arm todetect a portion of the power of the RF signal. The second coupler canfurther include a phase-shifting feature implemented with respect to atleast one of the driver and coupler arms to reduce a difference inphases of power ripples associated with the driver and coupler arms.

In some embodiments, the first coupler and the second coupler can beconnected in a chain configuration. The signal path trace for the firstcoupler can be an input for the chain configuration of the first andsecond couplers.

In some embodiments, at least some portions of the driver arm and thecoupler arm of the first coupler can form an overlapping region, and atleast one of the driver and coupler arms can have a non-straight armshape. The overlapping region can include a non-zero lateral offsetbetween the driver and coupler arms. In some embodiments, the RF modulecan be a front-end module.

In some teachings, the present disclosure relates to a radio-frequency(RF) device that includes a transceiver configured to process RFsignals, and an antenna in communication with the transceiver. Theantenna is configured to facilitate transmission of an amplified RFsignal. The RF device further includes an RF module connected to thetransceiver. The RF module is configured to generate and route theamplified RF signal to the antenna. The RF module includes a couplerassembly having a first coupler configured to detect power of theamplified RF signal. The first coupler includes a driver arm havinginput and output sides, and a coupler arm having input and output sidesand implemented relative to the driver arm to detect the power of theamplified RF signal. The first coupler further includes a phase-shiftingfeature implemented with respect to at least one of the driver andcoupler arms to reduce a difference in phases of power ripplesassociated with the driver and coupler arms. In some embodiments, the RFdevice can include a wireless device.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the inventions have been described herein. It isto be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment of the invention.Thus, the invention may be embodied or carried out in a manner thatachieves or optimizes one advantage or group of advantages as taughtherein without necessarily achieving other advantages as may be taughtor suggested herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a coupler having a driver arm and a coupler arm.

FIG. 2 depicts a multi-band radio-frequency (RF) module that can includeone or more couplers as described herein.

FIG. 3 shows a more specific example of FIG. 2, where a coupler assemblycan be implemented for power amplifier (PA) applications involving twobands.

FIG. 4 shows another example of FIG. 2, where a coupler assembly can beimplemented for power amplifier (PA) applications involving three bands.

FIGS. 5A and 5B show plan and sectional views of an edge-couplingconfiguration.

FIGS. 6A and 6B show plan and sectional views of a broad-side-couplingconfiguration.

FIGS. 7A-7C show perspective, plan, and sectional views of a couplerhaving a narrow broadside coupling configuration similar to the exampleof FIGS. 6A and 6B.

FIGS. 8A-8C show perspective, plan, and sectional views of a couplerhaving a driver arm with a side loop.

FIGS. 9A-9C show perspective, plan, and sectional views of a couplerhaving a driver arm with a Phi shape.

FIG. 10 shows examples of directivity values for the example couplerconfigurations of FIGS. 7A-7C, FIGS. 8A-8C, and FIGS. 9A-9C, as afunction of coupler length.

FIG. 11 shows examples of directivity values similar to the example ofFIG. 10, but with a different gap dimension between the driver andcoupler arms.

FIG. 12A shows a coupler having two C-shaped arms arranged in aback-to-back configuration.

FIG. 12B shows the coupler of FIG. 12A in which the driver and couplerarms can be laterally offset in one direction.

FIG. 12C shows the coupler of FIG. 12A in which the driver and couplerarms can be laterally offset in another direction.

FIG. 13 shows examples of coupling values for the example back-to-backC-shaped configuration of FIGS. 12A-12C as a function of lateralalignment offset.

FIG. 14 shows examples of directivity values for the exampleback-to-back C-shaped configuration of FIGS. 12A-12C as a function oflateral alignment offset.

FIG. 15 shows an example of arm shapes that can be implemented as avariation of the C-shaped configuration.

FIG. 16 shows another example of arm shapes that can be implemented as avariation of the C-shaped configuration.

FIG. 17 shows yet another example of arm shapes that can be implementedas a variation of the C-shaped configuration.

FIG. 18 shows yet another example of arm shapes that can be implementedas a variation of the C-shaped configuration.

FIG. 19 shows directivity curves as a function of frequency for theexample couplers of FIGS. 15-18.

FIG. 20 shows that in some embodiments, input and/or output tracesassociated with a coupler or a group of couplers can be dimensioned toachieve desired directivity values.

FIG. 21 shows a layout configuration that can be a more specific exampleof the configuration of FIG. 20.

FIG. 22 shows a coupler having two C-shaped arms arranged in aback-to-back configuration, similar to the example of FIG. 12A.

FIGS. 23A-23C show examples of how a coupler, such as the coupler ofFIG. 22, can be positioned depth-wise within a multi-layer substrate.

FIG. 24 shows various coupling plots for different combinations ofcoupler widths and coupler depth positions, as a function of couplerlength.

FIG. 25 shows various directivity plots for the same combinations as inFIG. 24, as a function of coupler length.

FIG. 26 shows that in some embodiments, a coupler can include aconfiguration for providing power ripple alignment to reduce error inpower detection.

FIG. 27 shows an example coupler depicted in an impedance representationto demonstrate where power ripples can occur.

FIG. 28 shows various P_(Lpk) plots as a function of VSWR, showingpossible magnitudes of load power ripple.

FIG. 29 shows various P_(Cpk) plots as a function of VSWR, showingpossible magnitudes of load power ripple.

FIG. 30 is similar to the example coupler configuration of FIG. 27, andfurther includes example power ripples at the load side of a driver armand at the output side of a coupler arm.

FIGS. 31A-31D show examples in which an adjustment can be made to thecoupler arm to move the phase of the coupler output side power ripplerelative to the phase of the load power ripple.

FIGS. 32A-32C show examples in which adjustments can be made to both ofthe driver and coupler arms to move the phases of the correspondingpower ripples relative to each other.

FIG. 33 shows an example of a coupler assembly having one or more phaseshifting features to move the phase(s) of the one or more power ripples.

FIG. 34 depicts an example module having one or more features asdescribed herein.

FIGS. 35A and 35B show examples of wireless devices having one or morefeatures as described herein.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The headings provided herein, if any, are for convenience only and donot necessarily affect the scope or meaning of the claimed invention.

Described herein are various examples related to couplers that can beconfigured for radio-frequency (RF) applications. FIG. 1 depicts acoupler 100 having a driver arm 102 implemented between first and secondnodes P1, P2, and a coupler arm 104 implemented between third and fourthnodes P3, P4. In some embodiments, the driver arm 102 can be a part ofan RF signal path such as an output path from a power amplifier (PA),and the coupler arm 104 can be a part of a power detection circuit.Various examples related to such a power detecting configuration aredescribed herein in greater detail.

In some embodiments, some or all of the driver arm 102 and the couplerarm 104, and/or pathways that connect such arms to their respectivenodes, can be configured to provide desirable performance properties.Examples of such desirable configurations are described herein ingreater detail.

In many RF applications, couplers such as 20 dB couplers or 20 dB chaincouplers are important parts in front-end module (FEM) products. Forexample, in a multi-band FEM, a chain coupler can be utilized. However,such a chain coupler can be difficult to design to meet specificationson available laminate technology due to, for example, limited size,multi-frequency operation, and lack of impedance tuning at couplertermination port. In another example, a coupler being utilized to detectand monitor RF output power typically needs to be accurate with minimaldetection error. However, a coupler rendering low power detection errorcan be difficult to design to meet specifications on available laminatetechnology due to, for example, some or all of the foregoing reasons.

In some embodiments, the coupler 100 of FIG. 100 can include one or morefeatures as described herein to yield improved performance and/orreduced detection error. In some embodiments, a plurality of suchcouplers can be implemented as a coupler assembly to allow, for example,efficient RF output power detection involving a plurality of frequencybands.

For example, FIG. 2 depicts a multi-band RF module 300 (e.g., a FEM)that can be configured to be capable of processing RF signals associatedwith a plurality of frequency bands. For the purpose of description, itwill be understood that “multi-band” can include two or more frequencybands such as cellular bands.

In the example of FIG. 2, the RF module 300 is shown to include an RFsignal processing circuit 112 configured to receive and process firstand second RF signals RF1_IN, RF2_IN and generate respective output RFsignals RF1_OUT, RF2_OUT. In some embodiments, such an RF signalprocessing circuit can include a power amplifier (PA) circuit configuredto amplify power of the input signals RF1_IN, RF2_IN. It will beunderstood that the RF module 300 can process (e.g., amplify) one of thetwo RF signals at a given time, both of the two RF signalssimultaneously, or any combination thereof.

Referring to FIG. 2, a coupler assembly 110 can be implemented in the RFmodule 300. In the example context of the RF signal processing circuit112 being a PA circuit, such a coupler assembly can be configured to,for example, detect power for some or all of the amplification pathsassociated with the PA circuit. In some embodiments, such a couplerassembly can include at least one coupler (e.g., 100 in FIG. 1) havingone or more features as described herein.

FIGS. 3 and 4 show more specific examples where a coupler assembly 110can be implemented in multi-band PA applications. In FIG. 3, amulti-band PA application can include two amplification paths. In FIG.4, a multi-band PA application can include three amplification paths. Itwill be understood that other numbers of amplification paths can beimplemented with a couple assembly having one or more features asdescribed herein.

In the example of FIG. 3, the example two-band configuration is shown toinclude a first amplification path configured to amplify an input signalRFin_1 to yield an output signal RFout_1, and a second amplificationpath configured to amplify an input signal RFin_2 to yield an outputsignal RFout_2. Each amplification path can include a PA and an outputmatching network (OMN). For the purpose of description, an assembly ofsuch PAs and OMNs of the first and second amplification paths can becollectively referred to as an RF signal processing circuit 112, similarto that of the example of FIG. 2.

In the example of FIG. 3, the example two-band configuration is shown tofurther include a coupler assembly 110 implemented as a chain coupler. Acoupler is shown to be implemented along the output side of thecorresponding PA, and two such couplers are shown to be chained togetherin series between detector nodes. More particularly, a first coupler 100a is shown to be implemented after the OMN of the first amplificationpath, and a second coupler 100 b is shown to be implemented after theOMN of the second amplification path. The first and second couplers 100a, 100 b are shown to be connected in series between the detector nodes.

In the example of FIG. 4, the example three-band configuration is shownto further include a third amplification path configured to amplify aninput signal RFin_3 to yield an output signal RFout_3. Such anamplification path can include a PA and an output matching network(OMN). For the purpose of description, an assembly of such PAs and OMNsof the three amplification paths can be collectively referred to as anRF signal processing circuit 112, similar to that of the example of FIG.2.

In the example of FIG. 4, the example three-band configuration is shownto further include a coupler assembly 110 implemented as a chaincoupler. A coupler is shown to be implemented along the output side ofthe corresponding PA, and three such couplers are shown to be chainedtogether in series between detector nodes. More particularly, inaddition to the first and second couplers that can be similar to theexample of FIG. 3, a third coupler 100 c is shown to be implementedafter the OMN of the third amplification path. The three couplers 100 a,100 b, 100 c are shown to be connected in series between the detectornodes.

In each of the examples of FIGS. 3 and 4, each amplification path isshown to be associated with a coupler. It will be understood that insome embodiments, an amplification path in such multi-bandconfigurations may or may not have a coupler. It will also be understoodthat the couplers in each of the examples of FIGS. 3 and 4 may or maynot be configured the same. It will also be understood that whilevarious examples are described herein in the context of chainedcouplers, one or more features of the present disclosure can also beimplemented in other types of couplers and coupler-assemblies.

FIGS. 5 and 6 show examples of common couplers that can be utilized in achain-coupler configuration. FIGS. 5A and 5B show plan and sectionalviews of an edge-coupled configuration, and FIGS. 6A and 6B show planand sectional views of a broad-side-coupled configuration.

Referring to FIGS. 5A and 5B, a driver arm 12 and a coupler arm 14 canbe implemented as conductive strips having a length L, respective widthsW1 and W2. Such conductive strips can be formed on a substrate layer 16so as to be separated by a gap dimension of d between the neighboringedges. In such a coupling configuration, the conductive strips of thedriver and coupler arms can have relatively large footprints. Further,the gap dimension d may need to be small so as to make fabricationdifficult, especially in mass-production applications.

Referring to FIGS. 6A and 6B, a driver arm 22 and a coupler arm 24 canbe implemented as conductive strips having a length L and a width W.Typically, the width W of such strips (22, 24) are smaller than thewidths of the example strips (12, 14) of FIGS. 5A and 5B, so as toprovide a narrow broadside coupling configuration. As shown in FIG. 6B,such a narrow broadside coupling can be implemented by forming one stripon one substrate layer (e.g., strip 24 on a substrate layer 26 b), andthe other strip on another substrate layer (e.g., strip 22 on asubstrate layer 26 a). In such a configuration, the upper and lowerstrips (22, 24) are shown to be separated by a distance d which can beapproximately the thickness of the substrate layer 26 a.

In the examples of FIGS. 5 and 6, it is noted that such couplerconfigurations can be implemented with relatively easy design androuting. Further, if implemented as a single coupler (e.g., forsingle-band application), such designs can include tuning withappropriate coupler termination impedance (e.g., fixed at 50 Ohm).However, in chain coupler implementations (e.g., multi-bandapplications) such tuning generally cannot be realized. As a result,directivity is typically difficult to improve in chain couplerconfigurations.

It is noted that power couplers such as 20 dB couplers and chaincouplers are important elements in multi-band multi-mode front endmodule (FEM) applications. For example, a coupler's directivity isimportant to system level power control accuracy and/or management.However, directivity is typically difficult to improve in commonly usedtechnologies such as laminate technology.

As described herein, in multi-band FEM product designs, a plurality ofcouplers operating at different frequency bands can be cascaded in achain so as to yield a chain coupler assembly. Good directivity can bemore difficult to achieve in such a chain coupler design.

FIGS. 7-33 show various non-limiting examples related to couplerconfigurations that can be implemented to provide performanceimprovements. FIGS. 7-25 generally relate to coupler features that canbe implemented to address directivity and/or coupling performance. FIGS.26-33 generally relate to coupler features that can be implemented toaddress power detection errors. It will be understood that in someembodiments, a coupler and/or an assembly of couplers can include one ormore features implemented to address either or both ofdirectivity/coupling performance and power detection performance.

In some embodiments, a chain coupler can be configured to include one ormore of features such as shape(s) of driver and/or coupler arms,alignment offset in broadside coupling, impedance control of inputand/or output traces, and depth-position in a substrate assembly. Forexample, FIGS. 7-11 show examples of how shape(s) of driver and/orcoupler arms can impact directivity performance. In another example,FIGS. 12-14 show examples of how alignment offset in broadside couplingcan impact coupling and directivity performance. In yet another example,FIGS. 15-19 show more specific examples of driver and/or coupler armshapes based on variations of C-shapes. In yet another example, FIGS. 20and 21 show examples of how input and/or output traces can be varied toobtain different directivity levels. In yet another example, FIGS. 22-25show examples of how depth-position of a coupler in a substrate assemblycan impact coupling and directivity performance.

FIGS. 7A-7C show perspective, plan, and sectional views of a couplerhaving a narrow broadside coupling configuration similar to the exampleof FIGS. 6A and 6B. In such a configuration, each of a driver arm 22 anda coupler arm 24 can be a relatively narrow and straight conductivestrip, and such strips can be separated by, for example, a laminatelayer. For the purpose of description related to FIGS. 7-11, such aconfiguration can be referred to as a line configuration, and also beconsidered to provide a base level of directivity performance.

FIGS. 8A-8C show perspective, plan, and sectional views of a coupler 100having a driver arm 102 and a coupler arm 104 that can be separated by,for example, a laminate layer. The driver arm 102 can include arelatively narrow and straight conductive strip 122, and a loop 124 thatextends generally parallel with the strip 122. The coupler arm 104 caninclude a relatively narrow and straight conductive strip that ispositioned approximately below the straight conductive strip 122 of thedriver arm 102. For the purpose of description related to FIGS. 7-11,such a configuration can be referred to as a loop configuration. It willbe understood that in some embodiments, the foregoing shapes of thedriver arm 102 and the coupler arm 104 can be interchanged.

FIGS. 9A-9C show perspective, plan, and sectional views of a coupler 100having a driver arm 102 and a coupler arm 104 that can be separated by,for example, a laminate layer. The driver arm 102 can include arelatively narrow and straight conductive strip 122, a first loop 124that extends generally parallel along the first side of the strip 122,and a second loop 126 that extends generally parallel along the secondside of the strip 122. Such first and second loops can be similar toeach other in dimensions so as to generally form a φ (Phi) shape. Thecoupler arm 104 can include a relatively narrow and straight conductivestrip that is positioned approximately below the straight conductivestrip 122 of the driver arm 102. For the purpose of description relatedto FIGS. 7-11, such a configuration can be referred to as a Phiconfiguration. It will be understood that in some embodiments, theforegoing shapes of the driver arm 102 and the coupler arm 104 can beinterchanged.

FIG. 10 shows examples of directivity values for the line (FIGS. 7A-7C),loop (FIGS. 8A-8C), and Phi (FIGS. 9A-9C) configurations as a functionof coupler length, obtained at an example frequency of 1.9 GHz. For thepurpose of description, such a coupler length can be the length of thestraight conductive strip (22 or 122). Three of the nine curvescorrespond to a width (of the straight conductive strip (22 or 122) andloop(s) (124, 126)) having a value of approximately 60 μm; another threecurves correspond to such a width having a value of approximately 80 μm;and the remaining three curves correspond to such a width having a valueof approximately 100 μm.

In the examples of FIG. 10, a gap between the driver arm 102 and thecoupler arm 104 is approximately 60 μm. FIG. 11 shows examples similarto those of FIG. 10, except that a gap between the driver arm 102 andthe coupler arm 104 is approximately 80 μm.

Referring to FIG. 10 (60 μm gap), a number of observations can be made.For example, for a given strip width (60, 80 or 100 μm), the loopconfiguration (FIGS. 8A-8C) provides generally higher directivity valuesthan the line configuration (FIGS. 7A-7C) throughout the example couplerlength range of 0.8 mm to 1.6 mm. Similarly, for a given strip width(60, 80 or 100 μm), the Phi configuration (FIGS. 9A-9C) providesgenerally higher directivity values than the line configuration (FIGS.7A-7C) throughout the example coupler length range of 0.8 mm to 1.6 mm.

Between the loop and Phi configurations, one can provide higherdirectivity than the other, depending on the strip width. For example,when the strip width is 60 μm, the Phi configuration provides higherdirectivity values than the loop configuration. When the strip width is80 μm, the Phi configuration generally provides higher directivityvalues than the loop configuration. However, the Phi configuration'sdirectivity decreases as the coupler length increases, and the loopconfiguration's directivity increases as the coupler length increases,such that at approximately 1.6 mm coupler length, the two configurationsprovide an approximately same directivity value. When the strip width is100 μm, the loop configuration provides significantly higher directivityvalues than the Phi configuration.

Referring to FIG. 11 (80 μm gap), trends similar to those of FIG. 10 canbe observed. More particularly, each of the loop and Phi configurationsprovides generally higher directivity values than the line configurationfor a given strip width (60, 80 or 100 μm).

Between the loop and Phi configurations, one can provide higherdirectivity than the other, depending on the strip width. Similar to theexample of FIG. 10, when the strip width is 60 μm, the Phi configurationprovides higher directivity values than the loop configuration. When thestrip width is 80 μm, the Phi configuration's directivity decreases asthe coupler length increases, and the loop configuration's directivityincreases as the coupler length increases (similar to the example ofFIG. 10) such that a cross-over in directivity curves occurs atapproximately 1.1 mm coupler length. Thus, when the coupler length isless than about 1.1 mm, the Phi configuration provides higherdirectivity values than the loop configuration; and when the couplerlength is greater than about 1.1 mm, the Phi configuration provideslower directivity values than the loop configuration. When the stripwidth is 100 μm, the loop configuration provides significantly higherdirectivity values than the Phi configuration, similar to the example ofFIG. 10.

Based on the foregoing examples related to FIGS. 7-11, one can see thatimproved and desirable coupler directivity performance can be achievedby configuring a coupler based on one or more of design parameters suchas coupler length, strip width, gap between the driver and coupler arms,and the shape of one or more of the driver and coupler arms.

FIGS. 12-14 show examples of how alignment offset in broadside couplingcan impact coupling and directivity performance. FIG. 12A shows aperspective view of a coupler 100 having a driver arm 102 and a couplerarm 104 that can be separated by, for example, a laminate layer or someother insulator layer. The driver arm 102 can be implemented in aC-shape that includes a straight section 140, and perpendicularextension sections from both ends of the straight section 140. Suchsections can be implemented as, for example, conductive strips so as toform the C-shape; and the ends of the extension sections can beconnected to their respective terminals. Similarly, the coupler arm 104can be implemented in a C-shape that includes a straight section 142,and perpendicular extension sections from both ends of the straightsection 142. Such sections can be implemented as, for example,conductive strips so as to form the C-shape; and the ends of theextension sections can be connected to their respective terminals.

In the example of FIG. 12A, the two C-shaped arms of the coupler 100 areimplemented so as to be in a back-to-back configuration when viewed fromabove. FIGS. 12B and 12C show such a plan view of the driver and couplerarms 102, 104. Each of the straight sections 140, 142 is shown to have alength of L and a width of W. In the example of FIG. 12B, a lateralalignment offset of A is in a direction where the perpendicularextension sections move away from each other from a position in whichthe straight sections 140, 142 are substantially aligned. For thepurpose of description of FIGS. 12-14, such a direction can beconsidered to be a positive direction. In the example of FIG. 12C, alateral alignment offset of A is in a direction where the perpendicularextension sections move toward each other from a position in which thestraight sections 140, 142 are substantially aligned. For the purpose ofdescription of FIGS. 12-14, such a direction can be considered to be anegative direction.

FIG. 13 shows examples of coupling values for the example back-to-backC-shaped configuration of FIGS. 12A-12C as a function of lateralalignment offset (A), for different combinations of length (L) and width(W). FIG. 14 shows examples of directivity values for the sameconfiguration of FIGS. 12A-12C as a function of lateral alignment offset(A), for the same combinations of length (L) and width (W).

Referring to FIG. 13, it is noted that coupling performance is optimalwhen lateral alignment offset (A) is approximately 0, and degrades asthe offset increases in either of positive and negative directions. Fora given length (L), the wider example (W=80 μm) has better couplingperformance in general than the narrower example (W=60 μm). For example,the curve for W=80 μm and L=1,200 μm is generally higher than the curvefor W=60 μm and L=1,200 μm. Similarly, the curve for W=80 μm and L=1,000μm is generally higher than the curve for W=60 μm and L=1,000 μm.

For a given width (W), the longer example (L=1,200 μm) has bettercoupling performance in general than the shorter example (L=1,000 μm).For example, the curve for W=80 μm and L=1,200 μm is generally higherthan the curve for W=80 μm and L=1,000 μm. Similarly, the curve for W=60μm and L=1,200 μm is generally higher than the curve for W=60 μm andL=1,000 μm.

Referring to FIG. 14, it is noted that directivity performance generallyincreases when lateral alignment offset (A) is increased in a positivedirection. For a given length (L), the narrower example (W=60 μm) hasbetter directivity performance in general than the wider example (W=80μm). For example, the curve for W=60 μm and L=1,200 μm is generallyhigher than the curve for W=80 μm and L=1,200 μm. Similarly, the curvefor W=60 μm and L=1,000 μm is generally higher than the curve for W=80μm and L=1,000 μm.

For a given width (W), the longer example (L=1,200 μm) has betterdirectivity performance in general than the shorter example (L=1,000μm). For example, the curve for W=80 μm and L=1,200 μm is generallyhigher than the curve for W=80 μm and L=1,000 μm. Similarly, the curvefor W=60 μm and L=1,200 μm is generally higher than the curve for W=60μm and L=1,000 μm.

Based on the foregoing examples related to FIGS. 12-14, one can see thatimproved and desirable coupling and/or directivity performance can beachieved by configuring a coupler based on one or more of designparameters such as coupler length, strip width, and lateral alignmentoffset between the driver and coupler arms. In some embodiments, one ormore of such design parameters can be selected for given shapes of thedriver and coupler arms (e.g., C-shaped arms).

FIGS. 15-19 show examples related arm shapes that can be implemented asvariations of the C-shaped example of FIGS. 12-14. In FIG. 15, a coupler100 is shown to include a driver arm 102 and a coupler arm 104 that canbe separated by, for example, a laminate layer or some other insulatorlayer. The driver arm 102 can be implemented in a C-shape that issimilar to the example of FIGS. 12-14, but with a section 152 that isoffset from a straight section 150 of the C-shape. Such an offsetsection is shown to be on the outer side of the C-shape of the driverarm 102.

In the example of FIG. 15, the coupler arm 104 is shown to beimplemented in a partial C-shape that is arranged with respect to thedriver arm 102 similar to the example of FIGS. 12-14. However, one ofthe two extension sections that define the C-shape along with thestraight section 154 is not present for the trace on the same level. Thecoupler arm 104 is also shown to include a section 156 that is offsetfrom the straight section 154 similar to that of the driver arm 102,such that the straight section/offset section combination (150/152) ofthe driver arm 102 generally overlaps with the straight section/offsetsection combination (154/156) of the coupler arm 104. In the coupler arm104, however, the offset section 156 is shown to be on the inner side ofthe partial C-shape of the coupler arm 104.

In FIG. 16, a coupler 100 is shown to include a driver arm 102 and acoupler arm 104 that can be separated by, for example, a laminate layeror some other insulator layer. The driver arm 102 can be implemented ina shape that is similar to a number “7”, such that an upper straightsection 160 is joined with a diagonal straight section 102. The couplerarm 104 is shown to include a straight section 164 that is dimensionedand arranged to be generally below the diagonal straight section 162 ofthe driver arm 102.

In the example of FIG. 15, the offset sections 152, 156 of the driverand coupler arms 102, 104 can be positioned at about mid-portions oftheir respective straight sections 150, 152. Lengths of such offsetsections can be about a third of the lengths of the straight sections.FIG. 17 shows an example where such offset sections can be relativelylonger, and also be positioned on one side of their respective straightsections.

In FIG. 17, a coupler 100 is shown to include a driver arm 102 and acoupler arm 104 that can be separated by, for example, a laminate layeror some other insulator layer. A straight section 170 is shown to bejoined to one end of an offset section 174 through a perpendicularsection 172. The other end of the offset section 174 is shown to bejoined to a terminal through another perpendicular section.

In the example of FIG. 17, the coupler arm 104 is shown to beimplemented in a shape that is arranged with respect to the driver arm102. More particularly, a straight section 176, a perpendicular section178, and an offset section 179 can be positioned below their respectivesections 170, 172, 174 of the driver arm 102. One end of the offsetsection 179 is shown to be connected to a terminal.

In FIG. 18, a coupler 100 is shown to include a driver arm 102 and acoupler arm 104 that can be separated by, for example, a laminate layeror some other insulator layer. The driver arm 102 can be implemented ina C-shape that is similar to the example of FIGS. 12A-12C. Moreparticularly, a straight section 182 and extension sections 180, 184 onboth ends of the straight section 182 are shown to form the C-shape. Inthe example of FIG. 18, the extension section 184 is shown to beconnected to a terminal, and the extension 180 is shown to be connectedto another terminal through a section that extends generally parallelwith the straight section 182.

In the example of FIG. 18, the coupler arm 104 is shown to beimplemented in a partial C-shape that is arranged with respect to thedriver arm 102. More particularly, a straight section 186 is shown to bepositioned below the straight section 182 of the driver arm 102. One endof the straight section 186 is shown to be connected to a terminal, andthe other end of the straight section 186 is shown to be connected toanother terminal through an extension section 188.

FIG. 19 shows directivity curves as a function of frequency for theexample couplers described in reference to FIGS. 15-18. Curve 190corresponds to the coupler 100 of FIG. 18, curve 192 corresponds to thecoupler 100 of FIG. 16, curve 194 corresponds to the coupler 100 of FIG.17, and curve 196 corresponds to the coupler 100 of FIG. 15.

Referring to FIGS. 15-19, it is noted that couplers having relativelysimpler C-shapes or variations thereof yield better directivityperformance than those having more complex shapes. For example, theexample couplers 100 of FIGS. 18 and 16 have relatively simple shapes(e.g., the overlapping portions between the driver and coupling arms arestraight sections without offset sections), and also yield significantlyhigher directivity levels than those of FIGS. 15 and 17.

It is further noted that the example C-shaped coupler configuration ofFIGS. 12A-12C can also be considered to have a relatively simple shape.Accordingly, and as shown in the example directivity plots of FIG. 14,such a C-shaped coupler configuration can yield directivity values ofabout 15 dB or higher with appropriate strip dimensions (e.g., 60 μmwidth, and length of 1,000 or 1,200 μm).

FIG. 20 shows that in some embodiments, input and/or output tracesassociated with a coupler or a group of couplers can be dimensioned toachieve desired directivity values. In the example of FIG. 20, a layoutconfiguration 200 is shown to include a coupler assembly 110. Such acoupler assembly can be provided with an input trace (CPL_in) 202 and anoutput trace (CPL_out) 204 to allow, for example, a control loopinvolving the coupler assembly 110.

FIG. 20 further shows that width of either or both of the input andoutput traces (W_in, W_out) can be selected to vary, for example,directivity values associated with the coupler assembly 110. It will beunderstood that the input and/or output traces can also be varied inother manners to vary performance parameters.

FIG. 21 shows a layout configuration 200 that can be a more specificexample of the layout 200 of FIG. 20. In the example of FIG. 21, acoupler assembly is shown to include a first coupler 100 a and a secondcoupler 100 b connected in a chain configuration. The first coupler 100a can be configured as a low-band (LB), and the second coupler 100 b canbe configured as a high-band (HB) coupler. It is noted that theparticular example of the second coupler 100 b is similar to the exampledescribed herein in reference to FIG. 16; however, it will be understoodthat other configurations can be utilized for the second coupler 100 b(and/or the first coupler 100 a).

In the example of FIG. 21, an input trace 202 is shown to provide aninput path on a substrate layer. Similarly, an output trace 204 is shownto provide an output path on the substrate layer.

Referring to FIGS. 20 and 21, widths of the input and output traces 202,204 can be varied to yield different directivity values. Table 1 listsexample widths of the input and output traces, and resulting directivityvalues for the first and second couplers (100 a, 100 b).

TABLE 1 Directivity D Directivity D of HB coupler of LB coupler CPL_inCPL_out (100b in FIG. 21) (100a in FIG. 21) width (μm) width (μm)(dB@1.9 GHz) (dB@1.9 GHz) 60 60 14.76306 17.16095 60 80 14.78385 17.469560 100 14.82659 17.75281 60 120 14.87157 18.03266 60 140 14.7878218.14788 60 160 14.74439 18.24034 80 60 14.56892 17.2613 80 80 14.6312417.4288 80 100 14.70594 17.76027 80 120 14.71349 17.94494 80 14014.63788 18.13349 80 160 14.56451 18.21632 100 60 14.60863 17.14364 10080 14.72178 17.50647 100 100 14.72579 17.56529 100 120 14.72165 17.95309100 140 14.53930 17.96083 100 160 14.48204 18.28411 120 60 14.5258417.12032 120 80 14.67376 17.43172 120 100 14.69399 17.66814 120 12014.62379 17.92033 120 140 14.59446 17.95774 120 160 14.37779 18.18755140 60 14.52359 17.28084 140 80 14.54188 17.61227 140 100 14.5973017.82707 140 120 14.54334 17.83687 140 140 14.50716 18.1119 140 16014.40882 18.16225

Referring to Table 1, it is noted that for the LB coupler (100 a in FIG.21), its directivity D can vary from a low value of 17.12 dB (120 μm and60 μm in widths of input and output traces) to a high value of 18.28 dB(100 μm and 160 μm in widths of input and output traces) to yield anoverall variation of about 1.2 dB. For the HB coupler (100 b in FIG.21), its directivity D can vary from a low value of 14.38 dB (120 μm and160 μm in widths of input and output traces) to a high value of 14.87 dB(60 μm and 120 μm in widths of input and output traces) to yield anoverall variation of about 0.5 dB.

FIGS. 22-25 show that in some embodiments, widths of driver and couplerarms of a coupler, as well as depth position of such a coupler in alayer assembly, can impact, for example, coupling and directivityperformance. For the purpose of description of FIGS. 22-25, a coupler100 having a C-shaped configuration similar to the example of FIGS.12A-12C is used, where the straight sections (140, 142 in FIGS. 12A-12C)generally overlap with no lateral offset. Referring to FIGS. 12A-12C and22, each of the straight sections (140, 142 in FIGS. 12A-12C) has alength L and a width W. It is noted, and as described in reference toFIGS. 12-14, a C-shaped coupler having a longer length (of the straightsection) provides better coupling performance and directivityperformance than shorter version. FIGS. 24 and 25 show examples of how awidth of the straight section can impact such coupler performance.

FIGS. 23A-23C show examples of how the coupler 100 of FIG. 22 can bepositioned depth-wise within a multi-layer substrate, and how such depthpositions can impact coupling performance and directivity performance. Afour-layer substrate structure is utilized for such a purpose; however,it will be understood that other numbers of layers can also be utilized.

In the example configuration of FIG. 23A, the driver arm 102 isimplemented on the top layer (Layer 1) 210 a, and the coupler arm 104 isimplemented on the next lower layer (Layer 2) 210 b. Accordingly, such aconfiguration is referred to as “L1/L2” in FIGS. 24 and 25. Similarly,and as shown in FIG. 23B, an “L2/L3” configuration involves the driverarm 102 on Layer 2 (210 b) and the coupler arm 104 on Layer 3 (210 c).Similarly, and as shown in FIG. 23C, an “L3/L4” configuration involvesthe driver arm 102 on Layer 3 (210 c) and the coupler arm 104 on Layer 4(210 d).

FIG. 24 shows various coupling plots for different combinations ofcoupler widths and coupler depth positions, as a function of couplerlength. FIG. 25 shows various directivity plots for the samecombinations, also as a function of coupler length.

Referring to FIG. 24, it is noted that in general, coupling performanceimproves with coupler length. For two example coupler widths (W=60 μmand 80 μm), it is noted that the wider coupler (W=80 μm) generally hasgreater coupling than the narrower coupler (W=60 μm), for a given depthposition. Among the three coupler depths (L1/L2, L2/L3 and L3/L4), it isnoted that a shallower position yields greater coupling than a deeperposition. More particularly,Coupling_(L1/L2)>Coupling_(L2/L3)>Coupling_(L3/L4).

Referring to FIG. 25, it is noted that in general, directivityperformance improves with coupler length. For two example coupler widths(W=60 μm and 80 μm), it is noted that the narrower coupler (W=60 μm)generally has significantly greater directivity than the wider coupler(W=80 μm), for a given depth position. Among the three coupler depths(L1/L2, L2/L3 and L3/L4), it is noted that in general, a deeper positionyields greater directivity than a shallower position. More particularly,Directivity_(L3/L4)>Directivity_(L2/L3)>Directivity_(L1/L2), for a givencoupler width.

In the example of FIG. 25, it is noted that directivity does not seem tovary much between the shallow (L1/L2) and mid (L2/L3) depths. In fact,for the wider coupler (W=80 μm), directivity for the shallow depth(L1/L2) is shown to be slightly higher than that of the mid-depth(L2/L3) configuration. However, it is noted that the deep (L3/L4)configuration shows consistently higher directivity performance than theother depth configurations.

Referring to the examples of FIGS. 24 and 25, coupling and directivityperformance can be adjusted by selecting an appropriate combination ofsome or all of design parameters such as coupler length, coupler width,and depth position of the coupler. Further, and as described herein,other design parameters such a coupler shape and input/output tracedimensions can also be considered when designing a coupler or a couplerassembly to yield desired performance parameters.

In some embodiments, a coupler or a coupler assembly having one or morefeatures as described herein can be utilized to provide advantageousimprovements in RF applications such as multi-band multi-mode (MBMM)front-end module (FEM) products. In such products, a chain coupler iscommonly utilized as an important component; however, traditionalcoupler termination tuning generally does not work in such a chaincoupler configuration.

In some embodiments, one or more features as described herein can beimplemented in a chain coupler to improve performance such asdirectivity. For example, and as described herein, placing a coupler onlower layers (e.g., L3/L4 in FIGS. 22-25) can improve directivity byabout 1 to 2 dB. In another example, configuring a coupler in arelatively simple C-shape or variation thereof (e.g., FIGS. 12, 16, 18)can improve directivity by about 3 to 4 dB. In yet another example, anoffset of alignment between driver and coupler arms (e.g., FIGS.12A-12C) can improve directivity by about 2 dB. In yet another example,configuring input and/or output traces (e.g., width adjustment in FIGS.20 and 21) can improve directivity by about 1 dB. When some or all ofthe foregoing designs are implemented together, significant overallimprovement in directivity can be realized.

FIGS. 26-33 generally relate to coupler features that can be implementedto address power detection errors. FIG. 26 shows that in someembodiments, a coupler 100 can include a configuration 220 for providingpower ripple alignment to, for example, reduce error in power detection.

It is noted that a power coupler is commonly utilized to detect and thuscontrol output power of a PA. Accordingly, minimal or reduced powerdetection error is desirable. It is further noted that an ideal couplertypically involves very high directivity and very low return loss;however, it is generally not possible or practical to meet such idealsettings in a real front-end product design. For example, directivity ofa coupler is difficult to improve in commonly used laminate technology.

In some embodiments, a coupler can be configured to yield acceptabledirectivity and return loss (e.g., as described herein), and powerripple phases at load side and at coupler output side can be aligned ormoved toward such alignment. As described herein, such an alignment ofphases can result in a significant reduction in power detection error.In some embodiments, such an alignment can be achieved by, for example,adjusting a phase delay between the load and the coupler output. Such aphase delay can be achieve by, for example, adjusting the shape and/ordimension of a trace associated with a coupler arm. Although variousexamples are described in the foregoing contexts, it will be understoodthat one or more features of the present disclosure can also beimplemented with other configurations.

It is further noted that an RF output return loss can also be animportant design factor. For example, a −20 dB return loss with perfectdirectivity can still cause a power error of 0.5 dB unmet in somedesigns.

It is further noted that in some designs, power detection error can bereduced or minimized by improving coupler directivity. However, acoupler's directivity can only be improved to a limited extent due to,for example, module size and technology being utilized.

In some embodiments, a coupler can be configured so that power ripplesat the load side of a driver arm and the output side of a coupler armare moved relative to each other to yield a desired reduction in powerdetection error. Such movement of the power ripples can include, forexample, adjusting phase(s) of either or both of the power ripples tosubstantially align, or move toward alignment of, the two phases.

FIG. 27 shows an example coupler depicted in an impedance representationto demonstrate where the foregoing power ripples can occur, and how suchpower ripples can be adjusted as described herein. A driver arm isindicated as 222, and a coupler arm is depicted as 224. The input sideof the driver arm 222 is shown to receive an RF signal (RFout) from, forexample, an output of a power amplifier. The output side of the driverarm 222 can be connected to a load, and therefore is indicated as theLoad side. The Load side is shown to be presented with a load impedanceZ_(L).

In the example of FIG. 27, the input side of the coupler arm 224 isindicated as CPLin, and the output side is indicated as CPLout. Thecoupler arm 224 is shown to present an impedance of Z_(T).

Referring to FIG. 27, it is noted that when Z_(T) is 50 Ohms and Z_(L)is not, the power at the load side of the driver arm (Load) can berepresented as

$\begin{matrix}{P_{Lpk} = {20\; {{\log \lbrack \frac{1 + {{\Gamma_{L}s_{33}}}}{1 - {{\Gamma_{L}s_{33}}}} \rbrack}.}}} & (1)\end{matrix}$

The power at the output side of the coupler (CPLout) can be representedas

$\begin{matrix}{{P_{Cpk} = {20\; {\log \lbrack \frac{1 + K}{1 - K} \rbrack}}},} & (2)\end{matrix}$

where K can be represented as

$\begin{matrix}{K = {{\frac{\Gamma_{L}{s_{31}/D}}{1 - {\Gamma_{L}s_{33}}}}.}} & (3)\end{matrix}$

In Equations 1-3 and FIG. 27, the input of driver arm 222 can be port 1,the output of the driver arm 222 (Load) can be port 2, the output of thecoupler arm 224 (CPLout) can be port 3, and the input of the coupler arm224 (CPLin) can be port 4. Accordingly, Γ_(L) (or s₂₂) representsreflection coefficient at the Load port and can be associated withvoltage standing wave ratio (VSWR), s₃₃ is representative of RF returnloss, s₃₁ represents coupling ratio, and D represents directivity.

FIG. 28 shows various P_(Lpk) plots as a function of VSWR, showingpossible magnitudes of load power ripple. Such P_(Lpk) plots are shownfor different values of return loss.

FIG. 29 shows various P_(Lpk) plots as a function of VSWR, showingpossible magnitudes of coupler side power ripple. Such P_(Lpk) plots areobtained at a given return loss value of −20 dB, and for variousdirectivity values as shown.

As described herein in reference to FIGS. 27-29 and Equations 1-3, it isnoted that the power ripple on the Load side can be affected by the loadVSWR and RF return loss, and the power ripple on the coupler output sidecan be affected by the load VSWR, RF return loss, and directivity.

FIG. 30 is similar to the example coupler configuration of FIG. 27, butalso depicts example power ripples at the Load side of the driver arm222 and at the output side of the coupler arm 224. More particularly,such power ripples can result when, for example, a uniform peak power isprovided at the input side of the driver arm 222. Such a uniform inputpeak power distribution is indicated as 230, and the resulting powerripple distributions at the Load side and the coupler output side areindicated as 232 and 238, respectively. Such power distributions areshown as a function of phase angle of the reflection coefficient(ang(Γ_(L))).

In the example of FIG. 30, the power ripple distribution on the Loadside (PLoad) is shown to include a peak 234. Similarly, the power rippledistribution on the coupler output side (PCpl) is shown to include apeak 238. Such power ripple peaks are shown to be not aligned in theexample of FIG. 30.

Referring to Equation 1, it is noted that at the peak 234 of PLoad(232), ∠Γ_(L)s₃₃=0. Referring to Equations 2 and 3, it is noted that atthe peak 238 of PCpl (236), ∠Γ_(L)s₃₃=0 also. Further,∠Γ_(L)s₃₁D=∠Γ_(L)s₃₁s₂₁/s₂₃=0, such that a condition ∠s₃₁s₂₁=∠s₃₃s₂₃ canapply.

As seen in the example of FIG. 30, the phase of the power ripple at Loadside is generally not the same as that at the coupler output side ingeneral. In such a situation, power detection error can be based on thedifference of the two ripples.

In some embodiments, one or more adjustments can be implemented in acoupler configuration to adjust the phase(s) of either or both of thepower ripples at the Load and coupler output sides. FIGS. 31A-31D showexamples in which an adjustment can be made to the coupler arm to movethe phase of the coupler output side power ripple relative to the phaseof the Load power ripple. FIGS. 32A-32C show examples in whichadjustments can be made to both of the driver and coupler arms to movethe phases of the corresponding power ripples relative to each other. Itwill be understood that an adjustment can be made to the driver arm tomove the phase of the Load power ripple relative to the phase of thecoupler output side power ripple.

In the examples of FIGS. 31A-31D, the driver arm is assumed to be fixed;accordingly, its power distribution on the Load side (P_Load) has asubstantially same phase among the four examples when an input power(P_Src) is applied. P_Load is shown to have a slight phase differencerelative to P_Src.

FIG. 31A shows an example of a coupler (output side) power distribution(P_cplr) that has the greatest phase difference (among the four examplesof FIGS. 31A-31D) relative to the phase of P_Load. Accordingly, theresulting power detection error of 1.1 dB is the worst among the fourexamples. FIG. 31C shows an example in which the phase differencebetween P_cplr and P_load is less than that of the example of FIG. 31A.Accordingly, the resulting power detection error of 0.96 dB is less thanthat of the example of FIG. 31A. Similarly, FIG. 31D shows an example inwhich the phase difference between P_cplr and P_load is less than thatof the example of FIG. 31D. Accordingly, the resulting power detectionerror of 0.47 dB is less than that of the example of FIG. 31D.Similarly, FIG. 31B shows an example in which the phase differencebetween P_cplr and P_load is the least among the four examples.Accordingly, the resulting power detection error of 0.15 dB is less thanthose of the examples of FIGS. 31A, 31C, 31D.

In the examples of FIGS. 32A-32C, both of the driver arm and the couplerarm can be adjusted to move the phases of the corresponding powerripples relative to each other. Power distributions for the Load (PLpk)and the coupler output (PCpk) are plotted along with corresponding powerdetection error distributions (240, 242, 244). Example amplitudes ofPLpk and PCpk are also shown.

In the example of FIG. 32C, the phases of PLpk and PCpk differ greatly,by about 180 degrees. Accordingly, the resulting power detection error(244) can be as high as about 1.8 dB. In the examples of FIGS. 32A and32B, the phase differences between PLpk and PCpk are much less than thatof FIG. 32C. Accordingly, the resulting power detection errors (240,242) are also less (about 0.5 dB or less).

FIG. 33 shows an example of a coupler assembly 110 having a firstcoupler configuration 100 a and a second coupler configuration 100 b.The first coupler configuration 100 a can be, for example, a high-band(HB) coupler, and the second coupler configuration 100 b can be, orexample a low-band (LB) coupler.

The first coupler configuration 110 a is shown to include a driver arm102 a having a curved shape (e.g., a partial loop) between itsterminals. The second first coupler configuration 110 b is shown toinclude a driver arm 102 b having a curved shape (e.g., a partialrace-track shape) between its terminals.

The first coupler configuration 100 a is shown to further include acoupler arm 104 a having a curved shape (e.g., a partial loop) betweenits terminals, so as to provide an overlapping section with respect tothe driver arm 102 a to thereby facilitate the coupling functionality.The second coupler configuration 100 b is shown to further include acoupler arm 104 b having a curved shape (e.g., a partial race-trackshape) between its terminals, so as to provide an overlapping sectionwith respect to the driver arm 102 b to thereby facilitate the couplingfunctionality.

In the example of FIG. 33, the coupler arm 104 a of the first coupler100 a is shown to be connected to the coupler arm 104 b of the secondcoupler 100 b so as to form a chain coupler configuration.

FIG. 33 further shows that in some embodiments, one or more coupler armsof a chain coupler can be configured to provide phase offset(s) tothereby move the corresponding power ripple(s) relative to thecorresponding power ripple(s) of the driver arm(s). As described herein,such phase offsets can reduce power detection errors.

In the example shown in FIG. 33, the coupler arm 104 a is shown toinclude a curved feature (e.g., a partial loop) indicated as 250,implemented to provide a phase offset for its power ripple. Similarly,the coupler arm 104 b is shown to have associated with it a plurality offeatures implemented to contribute to a phase offset for its powerripple. For example, a curved feature 252 between the first and secondcoupler arms 104 a, 104 b can be implemented to contribute to such aphase offset. Similarly, a complete loop 254 can be implemented tocontribute to such a phase offset. Similarly, a curved feature (e.g., apartial loop) 256 can be implemented to contribute to such a phaseoffset.

In the example of FIG. 33, it is noted that a feature implemented toprovide phase offset can be a part of an arm (e.g., a coupler arm) at aportion that overlaps with the other arm (e.g., a driver arm), a part ofan arm that does not overlap with the other arm, or any combinationthereof. It is further noted that while the examples in FIG. 33 showphase offsets being introduced with features of the coupler arms, itwill be understood that similar phase offsets can be introduced withfeatures associated with one or more driver arms.

As described herein, a coupler's power detection error can arise frompower ripples associated with the load side and the coupler output side.It is noted that when directivity of the coupler is very high, the powerdetection error can be mainly from the load power ripple. Whendirectivity is very low, the power detection error can be mainly fromthe coupler output power ripple.

In some embodiments, a coupler can be designed with good directivity byconsidering important contributors such as mutual coupling inductance.As described herein, such a coupler can also be configured so as toalign, or have closer alignment, of load and coupler output powerripples, so as to obtain a reduction in power detection error.

In the various examples described herein, various coupler designparameters such as coupler-related length, coupler-related width,coupler-related lateral offset, and coupler-related depth position arediscussed. For the purpose of description, it will be understood that acoupler having one or more features as described herein can have alength that is, for example, between 0.6 mm and 2.0 mm, between 0.8 mmand 1.6 mm, or between 1.0 mm and 1.4 mm. In some embodiments, such alength can be greater than, for example, 0.8 mm, 1.0 mm, 1.1 mm, 1.2 mm,1.3 mm, or 1.4 mm.

For the purpose of description, it will be understood that a couplerhaving one or more features as described herein can have a width thatis, for example, between 40 μm and 200 μm, between 50 μm and 160 μm,between 50 μm and 120 μm, between 50 μm and 100 μm, or between 50 μm and80 μm. In some embodiments, such a width can be less than or equal to,for example, 160 μm, 120 μm, 100 μm, 80 μm, or 60 μm.

For the purpose of description, it will be understood that a couplerhaving one or more features as described herein can have a lateraloffset magnitude that is, for example, between 0 μm and 60 μm, between 0μm and 50 μm, between 0 μm and 40 μm, between 0 μm and 30 μm, or between0 μm and 20 μm. In some embodiments, such a lateral offset magnitude canbe greater than, for example, 0 μm, 5 μm, 10 μm, 15 μm, or 20 μm.

In some implementations, one or more features described herein can beincluded in a module. FIG. 34 depicts an example module 300 thatincludes a power amplifier (PA) die 302 having a plurality of PAs 307 a,307 b. By way of examples, first and second PAs 307 a, 307 b are shownto receive and amplify input RF signals (RFIN_A, RFIN_B). Such amplifiedRF signals can be passed through respective output matching circuits 309a, 309 b, and be routed to respective outputs RFOUT_A, RFOUT_B.

The PAs 307 a, 307 b are shown to be in communication with abias/control circuit 305 (lines 306 a, 306 b). The bias/control circuit305 can be configured to provide bias and/or control functionality forthe PAs 307 a, 307 b based on, for example, a control signal input 304.In some embodiments, the bias/control circuit 305 can be implemented ina die that is separate from the PA die 302. In some embodiments, thebias/control circuit 305 can be implemented in the same die as the PAdie 302.

An output of the first matching network 309 a is shown to be connectedto a first coupler 100 a. Similarly, an output of the second matchingnetwork 309 b is shown to be connected to a second coupler 100 b. Eitheror both of the couplers 100 a, 100 b can include one or more features asdescribed herein.

In the example shown, the first and second couplers 100 a, 100 b areshown to be daisy-chained together between a coupler input 310 and anoutput 312. It will be understood that such couplers may or may not bechained together as shown.

In the example module 300 of FIG. 34, various components describedherein can be provided or formed on or within a packaging substrate 320.In some embodiments, the packaging substrate 320 can include a laminatesubstrate. In some embodiments, the module 300 can also include one ormore packaging structures to, for example, provide protection andfacilitate easier handling of the module 300. Such a packaging structurecan include an overmold formed over the packaging substrate 320 anddimensioned to substantially encapsulate the various circuits andcomponents thereon.

In some implementations, a device and/or a circuit having one or morefeatures described herein can be included in an RF device such as awireless device. Such a device and/or a circuit can be implementeddirectly in the wireless device, in a modular form as described herein,or in some combination thereof. In some embodiments, such a wirelessdevice can include, for example, a cellular phone, a smart-phone, ahand-held wireless device with or without phone functionality, awireless tablet, etc.

FIGS. 35A and 35B schematically depict an example wireless device 400having one or more advantageous features described herein. The exampleshown in FIG. 35A is for a frequency-division duplexing (FDD)configuration, and the example shown in FIG. 35B is for a time-divisionduplexing (TDD) configuration.

In each of the two example wireless devices of FIGS. 35A and 35B, PAs307, their input and output matching circuits (309), and couplingcircuits 100 can be implemented on a module 300 as described in FIG. 34.The PAs 307 can receive their respective RF signals from a transceiver410 that can be configured and operated in known manners. Thetransceiver 410 can be configured to generate the RF signals to beamplified and transmitted, and to process received signals. Thetransceiver 410 is shown to interact with a baseband sub-system 408 thatis configured to provide conversion between data and/or voice signalssuitable for a user and RF signals suitable for the transceiver 410. Thetransceiver 410 is also shown to be connected to a power managementcomponent 406 that is configured to manage power for the operation ofthe wireless device. Such power management can also control operationsof the baseband sub-system 408 and the module 300.

The baseband sub-system 408 is shown to be connected to a user interface402 to facilitate various input and output of voice and/or data providedto and received from the user. The baseband sub-system 408 can also beconnected to a memory 404 that is configured to store data and/orinstructions to facilitate the operation of the wireless device, and/orto provide storage of information for the user.

In the example wireless device 400 of FIG. 35A, outputs of the module300 are shown to be routed to an antenna 416 via their respectiveduplexers 410 a, 410 b and a band-selection switch 414. Theband-selection switch 414 can include, for example, asingle-pole-double-throw (e.g., SPDT) switch to allow selection of anoperating band. Although depicted in the context of the two-band outputof the module 300, it will be understood that the number of operatingbands can be different. In configurations where multiple bands areinvolved, such a band-selection switch can have, for example, an SPMT(single-pole-multiple-throw) configuration.

In the example of FIG. 35A, each duplexer 410 can allow transmit andreceive operations to be performed substantially simultaneously using acommon antenna (e.g., 416). In FIG. 35A, received signals are shown tobe routed to “Rx” paths (not shown) that can include, for example, alow-noise amplifier (LNA).

In the example wireless device 400 of FIG. 35B, time-division duplexing(TDD) functionality can be facilitated by filters 412 a, 412 b connectedto the two example outputs of the module 300. The paths out of thefilters 412 a, 412 b are shown to be connected to an antenna 416 througha switch 414. In such a TDD configuration, Rx path(s) can come out ofthe switch 414. Thus, the switch 414 can act as band selector (e.g.,between high-band and low-band as described herein), as well as a Tx/Rx(TR) switch.

In the example wireless devices 400 depicted in FIGS. 35A and 35B, theexample module 300 is depicted as including the PAs (307 a, 307 b) andtheir respective matching circuits (309 a, 309 b), and coupler sections(100 a, 100 b). In some embodiments, the module 300 of FIG. 35A caninclude some or all of the duplexers 410 a, 410 b and the switch 414. Insome embodiments, the module 300 of FIG. 35B can include some or all ofthe filters 412 a, 412 b and the switch 414.

A number of other wireless device configurations can utilize one or morefeatures described herein. For example, a wireless device does not needto be a multi-band device. In another example, a wireless device caninclude additional antennas such as diversity antenna, and additionalconnectivity features such as Wi-Fi, Bluetooth, and GPS.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The word “coupled”, as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Additionally, the words “herein,” “above,” “below,” and words of similarimport, when used in this application, shall refer to this applicationas a whole and not to any particular portions of this application. Wherethe context permits, words in the above Description using the singularor plural number may also include the plural or singular numberrespectively. The word “or” in reference to a list of two or more items,that word covers all of the following interpretations of the word: anyof the items in the list, all of the items in the list, and anycombination of the items in the list.

The above detailed description of embodiments of the invention is notintended to be exhaustive or to limit the invention to the precise formdisclosed above. While specific embodiments of, and examples for, theinvention are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. For example, whileprocesses or blocks are presented in a given order, alternativeembodiments may perform routines having steps, or employ systems havingblocks, in a different order, and some processes or blocks may bedeleted, moved, added, subdivided, combined, and/or modified. Each ofthese processes or blocks may be implemented in a variety of differentways. Also, while processes or blocks are at times shown as beingperformed in series, these processes or blocks may instead be performedin parallel, or may be performed at different times.

The teachings of the invention provided herein can be applied to othersystems, not necessarily the system described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

While some embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the disclosure. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the disclosure.

1. A coupler for detecting power of a radio-frequency (RF) signal, thecoupler comprising: a driver arm configured to route the RF signal; anda coupler arm implemented relative to the driver arm to detect a portionof the power of the RF signal, portions of the driver arm and thecoupler arm forming an overlapping region, at least one of the driverand coupler arms having a non-straight arm shape, the overlapping regionincluding a non-zero lateral offset between the driver and coupler arms.2. The coupler of claim 1 wherein the non-straight arm shape includes astraight section and a first side loop extending parallel with thestraight section implemented as part of the driver arm.
 3. The couplerof claim 2 wherein the non-straight arm shape further includes a secondside loop extending parallel with the straight section to form a Phishape.
 4. The coupler of claim 1 wherein the driver arm includes aC-shape as the non-straight arm shape.
 5. The coupler of claim 4 whereinthe coupler arm includes a C-shape as the non-straight arm shape.
 6. Thecoupler of claim 5 wherein the C-shapes of the driver and coupler armsare arranged in a back-to-back configuration such that portions ofstraight sections of the C-shapes form the overlapping region.
 7. Thecoupler of claim 6 wherein the lateral offset includes the straightsections of the C-shapes being moved away from each other.
 8. Thecoupler of claim 1 wherein the driver arm includes a 7-shape as thenon-straight arm shape.
 9. The coupler of claim 8 wherein coupler armincludes a straight section that forms the overlapping region with astraight section of the 7-shape.
 10. The coupler of claim 1 furtherincluding a phase-shifting feature implemented with respect to at leastone of the driver and coupler arms to reduce a difference in phases ofpower ripples associated with the driver and coupler arms.
 11. Aradio-frequency (RF) module comprising: a packaging substrate havingmultiple layers; a plurality of power amplifiers (PAs) implemented onthe packaging substrate; and a coupler assembly implemented relative tothe packaging substrate and including a first coupler configured todetect power of an RF signal amplified by a first PA, the first couplerincluding a driver arm configured to route the RF signal, and a couplerarm implemented relative to the driver arm to detect a portion of thepower of the RF signal, portions of the driver arm and the coupler armforming an overlapping region, at least one of the driver and couplerarms having a non-straight arm shape, the overlapping region including anon-zero lateral offset between the driver and coupler arms.
 12. The RFmodule of claim 11 wherein the packaging substrate includes a laminatesubstrate having four or more layers having a layer number i beginningwith 1 for the uppermost layer.
 13. The RF module of claim 12 whereinthe driver arm is implemented over an i-th layer, and the coupler arm isimplemented below the i-th layer.
 14. (canceled)
 15. (canceled)
 16. TheRF module of claim 11 wherein the coupler assembly further includes asignal path trace for one side of the coupler arm, the signal path traceconfigured to improve directivity performance of the coupler assembly.17. The RF module of claim 16 wherein the coupler assembly furtherincludes a second coupler configured to detect power of an RF signalamplified by a second PA, the second coupler including a driver armconfigured to route the RF signal, and a coupler arm implementedrelative to the driver arm to detect a portion of the power of the RFsignal.
 18. The RF module of claim 17 wherein portions of the driver armand the coupler arm of the second coupler form an overlapping region, atleast one of the driver and coupler arms having a non-straight armshape, the overlapping region including a non-zero lateral offsetbetween the driver and coupler arms.
 19. The RF module of claim 17wherein the first coupler and the second coupler are connected in achain configuration.
 20. The RF module of claim 19 wherein the signalpath trace for the first coupler is an input for the chain configurationof the first and second couplers.
 21. (canceled)
 22. The RF module ofclaim 11 wherein the coupler assembly further includes a phase-shiftingfeature implemented with respect to at least one of the driver andcoupler arms of the first coupler to reduce a difference in phases ofpower ripples associated with the driver and coupler arms. 23.(canceled)
 24. A radio-frequency (RF) device comprising: a transceiverconfigured to process RF signals; an antenna in communication with thetransceiver, the antenna configured to facilitate transmission of anamplified RF signal; and an RF module connected to the transceiver, theRF module configured to generate and route the amplified RF signal tothe antenna, the RF module including a coupler configured to detectpower of the amplified RF signal, the coupler including a driver armconfigured to route the amplified RF signal, and a coupler armimplemented relative to the driver arm to detect a portion of the powerof the amplified RF signal, portions of the driver arm and the couplerarm forming an overlapping region, at least one of the driver andcoupler arms having a non-straight arm shape, the overlapping regionincluding a non-zero lateral offset between the driver and coupler arms.25. (canceled) 26-50. (canceled)